Efficacy of silver ion-containing dressing in the management of exit site granuloma in patients on peritoneal dialysis: A case series

Introduction

Peritoneal dialysis (PD) is a life-sustaining therapy for patients with end-stage renal disease but is associated with complications, such as exit site infection (ESI), which can lead to peritonitis and catheter loss. Reported to occur in 5% of patients on PD annually, granuloma formation is a common inflammatory reaction on the catheter exit site and may be caused by excessive tension due to improper catheter fixation or exit site trauma. ¹ We often encounter granulomas in patients with pericatheter pocket formation caused by epidermal downgrowth over the course of prolonged PD treatment. If left untreated, granulomas can exacerbate infection risk, necessitate antibiotic therapy, and even require catheter replacement. Therefore, in its 2023 update, the International Society for PD (ISPD) Catheter-related Infection Recommendations suggested silver ion-containing dressings as a potential intervention and management strategy for exit site complications, such as granulomas. ¹ Silver ion dressings were reported to prevent infection and promote wound healing by releasing a low level of active silver ions into the wound fluid or secretion. ² However, there is limited clinical evidence supporting their efficacy in the management of exit site granulation in patients on PD. Here, we presented five patients on PD who exhibited significant resolution of granulation tissue after application of silver ion-containing dressings.

Case report

Approximately 20 patients receiving peritoneal dialysis are managed annually at our hospital, including outpatients as well as inpatients referred from other clinics for peritoneal dialysis–related complications or surgical procedures. During the period from 2023 to 2024, exit-site granulomas were observed in five patients. At our hospital, the usual care for PD exit site comprises disinfection once a day using cotton balls moistened with chlorhexidine; protection with dressing materials, such as sterile gauze; and fixation or immobilization of catheter placement. For five patients with exit site granulomas, silver ion dressings are cut into strips and individually adapted to each exit site shape to ensure that the granulomas are reached (Figure 1(a)). For exit sites with pericatheter pocket formation, we use cotton swabs instead of cotton balls for disinfection to ensure that the pocket interior is reached (Figure 1(b)).

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Figure 1.

Modified exit site care technique for patients on peritoneal dialysis with downgrowth on catheter exit sites: (a) silver ion dressing sheets are cut into narrow strips and inserted into the sinus of the exit site to ensure that the dressing reaches the granulation tissue and (b) a small cotton swab is used to disinfect an exit site with downgrowth to ensure adequate cleaning of the exit site sinus.

In all five patients, a straight catheter with three cuffs (Long Shoot Catheter, Hayashidera Medinol, Ishikawa, Japan) was inserted, with the external cuff positioned approximately 5 cm from the exit site.

After initiating exit-site care using silver ion–containing dressings, we examined the patients’ exit sites at least once a week, assessing for the presence of purulent discharge at the exit site and for any signs of tunnel infection. All five patients used silver ion dressings for 4–6 weeks until resolution of the exit-site granulomas, after which the dressings were continued for several additional months to monitor for granuloma recurrence.

Case 1

A 41-year-old woman who had IgA nephropathy and received previous antibiotic treatment for ESI developed a small granuloma on the peritoneal exit site (Figure 2(a)). The granuloma disappeared completely after almost 5 weeks of dressing the exit site with silver ion pads containing 1.2% silver (AQUACEL Ag Advantage, Convatec Limited, UK) daily by herself.

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Figure 2.

Representative appearances of exit site granulomas in five patients on peritoneal dialysis before treatment with silver ion-containing dressings (arrow): (a) protruding granuloma is seen at the 6 o’clock position. Granulomas are seen at the (b) 9 o’clock, and (c) 6 o’clock positions. (d) Extensive granuloma formation extending from the 12 to the 5 o’clock positions and involving almost half of the exit site circumference is shown. Granuloma is seen at the (e) 3 o’clock position.

Case 5

A 70-year-old woman with hypertensive nephrosclerosis and history of multiple ESIs developed peritoneal ESI and granuloma (Figure 2(e)). The patient was instructed to apply AQUACEL Ag Advantage daily on the exit site. After almost 6 weeks, the granuloma resolved completely.

All patients experienced remarkable complete resolution of granulation tissue without requiring additional treatment. No patients developed PD catheter tunnel infection or required topical or systemic antibiotic therapy (Table 1).

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Table 1.

Baseline characteristics and clinical outcomes of five patients on PD who had exit site granuloma treated with silver ion-containing dressings.

Variable	Case 1	Case 2	Case 3	Case 4	Case 5
Age, years	41	51	52	75	70
Sex	F	M	M	F	F
PD duration, years	2	3	3	3	2
Underlying disease	IgA nephropathy	Postrenal kidney disease	Alport syndrome	Lupus nephritis	Nephrosclerosis
Culture	Absence of purulent discharge	Group B Streptococcus	Absence of purulent discharge	Absence of purulent discharge	Absence of purulent discharge
Granuloma	Figure 2(a)	Figure 2(b)	Figure 2(c)	Figure 2(d)	Figure 2(e)
Outcome	Recovered after 6 weeks	Recovered after 5 weeks	Recovered after 4 weeks	Recovered after 6 weeks	Recovered after 5 weeks

PD: peritoneal dialysis.

Discussion

In patients on PD, ESI is an important complication that can lead to peritonitis and withdrawal from PD. Untreated granulomas may increase susceptibility to infection and often necessitate prolonged antibiotic use or even catheter replacement. The ISPD Catheter-related Infection Recommendations: 2023 Update enlisted several treatment options, such as silver nitrate cauterization, topical chlorhexidine application, and silver ion-based dressing, for granulomas. ¹ Silver nitrate cauterization is commonly applied, but it can lead to skin burns and pain. ¹ A randomized controlled trial on 44 patients reported that chlorhexidine swab sticks achieved a similar healing rate with silver nitrate but were associated with less pain and fewer side effects, such as burning and staining near the exit site. ³ This case series demonstrated that application of silver ion-containing dressings was a promising intervention for five patients on PD who developed peritoneal exit site granulation tissue, which needed additional care to prevent exacerbated breakdown.

Granulomas are frequently observed at the exit sites of indwelling medical devices, including peritoneal dialysis catheters, tracheostomy tubes, and suprapubic catheters, and are thought to be associated with repetitive mechanical irritation of the skin by these devices. Over-granulated exit sites may cause patient discomfort and can serve as a nidus for infection or bleeding. Once infection develops, management may become challenging and can ultimately result in catheter removal and interruption of therapy; in severe cases, systemic infection such as sepsis may occur. A granuloma comprises a disorganized and exuberant granulation response with varying degrees of inflammation, which is accompanied by macrophage accumulation to attempt removal of the catheter. ³ Histologically, granulomas are characterized by excessive and irregular granulation tissue accompanied by variable degrees of inflammation. ³ Granulomas at the exit site may prevent epithelial cells from migrating across the wound surface and create a moist and delicate surface that can facilitate bacterial growth, potentially increasing the risk of exit-site and tunnel infections.

Silver ions exert antimicrobial effects by disrupting bacterial cell wall, inhibiting replication, and preventing biofilm formation. ⁴ In addition to infection control, silver dressing promotes tissue healing and reduces inflammation on the exit site. Silver ions have been shown to exert inhibitory effects on both Gram-positive and Gram-negative bacteria. ⁵ The antibacterial activity of silver ions is largely attributed to their strong capacity to disrupt the transport and release of potassium ions from bacterial cells and to interfere with adenosine triphosphate synthesis. ⁶ In addition, silver ions readily interact with various biomolecules, including deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and peptides, leading to the formation of insoluble complexes that hinder bacterial cell division and replication. ⁷ Silver ion–containing dressings release low concentrations of a low level of active silver ions on the wound surface and may promote wound healing by maintaining a moist environment in addition to suppressing bacterial growth, thereby contributing to the improvement of refractory granulomatous lesions.

Previous studies have established the efficacy of silver-based products in wound care. Mondal et al. reported that silver dressings significantly reduced bacterial load and accelerated wound healing of chronic ulcers. ⁸ Matinfar et al. reported a case of large exit-site granuloma refractory to antimicrobial therapy, in which treatment with silver ion-based dressing resulted in regression of the lesion. ⁹ Although several reports have indicated that silver ion dressings promoted healing of refractory wounds, ² only few reports have revealed these effects on exit site granulomas in patients on PD. To the best of our knowledge, this report was the first case series to demonstrate the efficacy of silver ion dressings for exit site granulomas. Furthermore, this report highlighted the effectiveness of silver ion dressings for granulation tissue, regardless of the underlying disease, such as diabetes or SLE.

Causes and prevention of exit-site granuloma in PD patients

Granuloma frequently occurs at the exit sites of medical devices, including peritoneal dialysis catheters, and is thought to result from chronic mechanical irritation and repeated minor trauma to the surrounding skin. Preventing granuloma formation is an important aspect of exit-site management. In addition to inadequate PD catheter fixation, exit-site morphological changes associated with long-term peritoneal dialysis, including changes in body shape and skin laxity, may be associated with granuloma development. At our hospital, individualized exit-site design is carefully planned prior to PD catheter insertion; however, over time, the skin defect may become larger than the PD tube itself, potentially contributing to granuloma formation. In the present case series, all five patients had been receiving peritoneal dialysis for more than 2 years, and their exit sites showed a size discrepancy between the skin defect and the PD tube. In patients undergoing long-term peritoneal dialysis, particular attention should be paid to exit-site granulomas, and healthcare providers should carefully monitor the exit sites. In addition, it has been reported that proper PD catheter immobilization and avoidance of mechanical stress on the exit site may be useful in lowering exit-site infection rates; these approaches might also be applicable to the prevention of granuloma formation. ¹⁰ Ongoing patient education provided by nurses regarding exit-site care, catheter fixation, and granuloma management may improve self-care and help prevent exit-site infections and appears to play an important role alongside appropriate dressing selection.

Moreover, the nephrotoxicity of vancomycin, which is a frequently used antibiotic to treat ESIs, can lead to loss of residual renal function, which may require discontinuation of PD in some patients. Furthermore, systemic antibiotic administration can contribute to the emergence of resistant bacteria. The use of silver ion–containing dressings for exit-site granulomas may contribute to the prevention of exit-site or tunnel infections and may reduce the need for antimicrobial therapy, which could in turn help limit the emergence of antimicrobial resistance and support the continuation of peritoneal dialysis.

Although silver ion–containing dressings can be a useful adjunct in the treatment of exit-site granulomas, their effectiveness may be limited in the presence of active infection. When purulent discharge or signs suggestive of tunnel infection are observed, antimicrobial therapy should be promptly initiated in accordance with ISPD Catheter-related Infection Recommendations: 2023 Update. In our cases, patients were examined at least once a week, and none showed purulent discharge or signs suggestive of tunnel infection during follow-up.

In conclusion, this case series suggests that silver ion–containing dressings may serve as a useful adjunct in the local management of exit-site granulomas by supporting infection control and wound healing when used as part of comprehensive exit-site care, including appropriate catheter fixation and ongoing patient education. Further studies are warranted to better define their role and optimal indications in catheter exit-site care.

Conclusions

In these five patients on PD who developed exit site granulomas, silver ion-containing dressings appeared to be an effective and noninvasive management option. This intervention led to successful resolution of granulation tissue without the need for antibiotics or additional medical interventions. Further larger-scale clinical studies are warranted to validate these findings and establish definitive clinical guidelines.